Overmolding for device controller panel


Manufacturing Services: 

plastic injection molding, CNC milling, EDM machining

Part Material: Hard material:PC-203, Soft material: TPE-70A

Tool Material: NAK80

About Customer

The client has cooperated with us on many projects, mainly in the electrical industry, such as high voltage and low voltage monitor.

About this Project

This project is overmold injection molding technology, it is an instrument control panel.

As the customer's products are used for outdoor testing, the material is required to have good high temperature resistance properties, while the use of transparent materials.

According to our project experience, for hard material, we recommend PC-203 and make high polish in the clear surface. For soft material, TPE-70A is best to be coated with hard material and make texture process in the surface.

Material Analysis

Mold steel, we choose NAK80, this kind of steel has good corrosion resistance.

As for the product part, the hard resin needs to be transparent and used outdoors, so the material needs to be resistant to high temperature and has good flame-retardant characteristics. We recommend PC-203.

Soft material needs to have good adhesion to do overmolding, it needs to be tightly wrapped in the hard plastic part, we recommend TPE-70A.

Design for Manufacturing Review

After receiving the customer's product drawing, our engineers will make a detailed DFM report, pointing out the product's injection gate, product wall thickness, whether the structure needs to have minor changes, and propose the optimal design solution for the customer's reference.

Wall Thickness

In the TPE parts, there are four positions need to be reduced material because the thickness is too thick. It may occur to shrinkage.

Gate Location

In order to ensure the good appearance of the product, we add three banana gates to injection, the gate size is Ø1.2MM.

Surface Finish

We provide one stop solution for our customers, also including surface treatment, like polish, matte, electroplating, etc. In the transparent hard parts, customer required us to do high polish, we make polish 800μ.  For the soft TPE part, the customer wanted a textured surface, we sent our board to him, and he chose the surface of VDI 27.

Challenges of overmold injection molding

1.Size deviation: Material shrinkage rate needs to be considered when designing the overmolding mold. When do the first step injection molding, shrinkage rate must be considered. But the second step overmolding do not need.

2.Product damage the mold: This situation generally occurs in the second step molding process. When the first step product is put into the second molding, the position of the product need carefully checks, otherwise it will result in mold damages.

3.Cannot be overmolded: When do overmolding, it is recommended to choose a special material. And when do second molding, it is necessary to remove the dust on the first molding part surface.

4.Material missing when do second molding: TPE is generally used for overmolding. The flowability of TPE is not so good, so there will be situations such as poor overmolding and material missing. It is necessary to readjust the injection molding parameters to improve the cycle time.

Final Mold Tool Making

Through our cooperation and experience, we finally presented the perfect product to customers.

The client trusts us so much that the new projects in the later stage are handed over to our team.

We hope that in this case study you were able to find useful information. Send us your inquiry, you can get a free quotation now!